Field of Invention
The field of the invention is that of electrical contact materials, and the invention relates more particularly to a method of preparing silver-based oxide electrical contact materials with fiber-like arrangement.
Description of Related Arts
The rapid development of the electrical industry places an increasingly high requirement for the improvement of the performance of the silver-based electrical contact materials. Therefore, a silver-matrix composite intended for better electrical and mechanical performance has been developed to replace the traditional silver-based contact materials. Furthermore, silver-based oxide composites with fiber-like arrangement which have high resistance to welding and arc erosion and good processing performance have attracted great interests of researchers in recent years. However, silver-based oxide materials have not been widely promoted and applied due to its complex preparation process, high cost, and difficulties involved in the secondary processing. Therefore, the development of a simple and practical method which can be applied to mass production is urgently called for in current research.
By retrieving domestic and foreign research on silver-based oxide electrical contact materials with fiber-like arrangement, a Chinese invention patent is discovered and it is described as follows: Silver-based Electrical Contact Materials with Fiber-like Arrangement and Preparation Method thereof, application number: 200910196283.0, Publication Number: CN101707145A.
At present, there are basically two methods of preparing silver-based oxide electrical contact materials with fiber-like arrangement. The first is the traditional powder metallurgy sintering extrusion method and its modification with improved extrusion for increased processing deformation. The main process is as follows: powder mixing→pressing→sintering→extruding→drawing→annealing→drawing→products. The fiber-like arrangement prepared by this method is not neatly displayed and not suitable for the reinforcing phase with poor plasticity and ductility. Furthermore, large particles of the reinforcing phase may affect product performance. The second method combines the green body pre-design with extrusion. To be more precisely, a certain number of reinforcing phase wire materials are fixed in the matrix by mold in advance, and then isostatic-pressed, sintered and extruded in turn [Literature: CN101707145A]. Although a neat and continuous fiber-like structure can be achieved through this method, it cannot be applied to the large-scale production. There are mainly two reasons: one is that the process is rather complex and requires pre-preparation of the particles reinforcing silver-based wire materials which are to be fixed in the matrix by mold; the other is that the process has specific requirement on the plasticity and ductility of the reinforcing phase wire materials.